The present invention relates to bearings in general, and more particularly to spherical and cylindrical bearings wherein the engaged bearing surfaces of an inner member and of an outer member are pre-loaded toward each other. The present invention contemplates that the bearing surfaces in engagement be provided with a particular geometry different at the time of manufacturing from the geometry which is finally obtained after a wear-in period.
The invention has particular applications to spherical bearings of the ball and socket type as are of general use in motor vehicle steering tie-rod assemblies, for example, and to both cylindrical and spherical bearings which are of general use in drag links, torque rods, suspension stabilizers, shock absorbers and friction snubbers, for example, in passenger cars, trucks, trailers, military vehicles, railroad vehicles, and the like.
It is customary to manufacture ball and socket bearings and cylindrical bearings for such use under exacting machining and assembly requirements, in order to provide heavy load bearing capability and long life under adverse conditions. For example, bearing surfaces in swivelling or rotary engagement are usually machined to the geometric shapes and to dimensions as accurate as technically feasible, with narrow tolerances and with exacting surface finishes. Such methods of manufacturing are not compatible with mass production at a reasonably low cost per unit, and the tolerances required may lead to bearing lock-up during assembly or after installation on a vehicle.